Application of GIS for water quality monitoring in the aquaculture impacted Rawang sub-basin of the Selangor river, Malaysia

Freshwater aquaculture is a prominent activity in Rawang sub-basin of the Selangor River. Despite the importance good water quality in daily life, there is limited study on the impact of aquaculture activities on water quality. This paper discusses water quality parameter status (pH, dissolved oxygen (DO), ammoniacal nitrogen, turbidity, total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD)) based on Water Quality Index (WQI) in the aquaculture-impacted Rawang sub-basin of Selangor River and develops the Inverse Distance Weighted (IDW) maps showing water quality status by using GIS (ArcGIS 10.2.1 software) in order to identify the potential aquaculture impacted sites. Seven river sampling sites were selected including Guntong (SR1), Guntong’s tributaries (SR2/control), Kuang (SR3 and SR7), Gong (SR4), Buaya (SR5), and Serendah (SR6) using random sampling techniques based on accessibility and proximity to aquaculture farms. Seven water quality parameters were recorded and analysed on a bi-monthly basis. Results revealed that Guntong, Kuang, Buaya and Serendah rivers had moderate water quality, whereas Gong River was significantly polluted. The control river recorded clean water quality status. One-way analysis of variance (ANOVA) showed that there were significant differences in all measured water quality parameters among sampling sites (P